Pneumatic thread control system for looms



July 15, 1941. R. G. TURNER 2,249,406

PNEUMATIC THREAD CONTROL SYSTEM FOR LOOMS Filed Jan. 4, 1940 y 2 Sheets-Sheet 1 INvEN-l-ow` RscHARo @.TURNE# July l5, 1941. R, G, TURNER i 2,249,406

PNEUMATIC THREAD CONTROL SYSTEM FOR LOOMS Filed Jan. 4, 1940 2 Sheets-Sheet 2 FIG. 1H

lNvl-:NTQR Rlcn-ARD Gr. TUR NER A-r-roRNEY Patented July 15, 1941 UNIT-so sTI riss naar

lreirse 2,249,406 PNEUMeTro THREAD CONTROL SYSTEM FUR LOOMS Richard G. Turner, Wr'ce'ster, Mass., assigner `to Crompton & Knowles Loom Works, Worcester,y Massga corporation of Massachusetts Application January fi, 1946, Serial No. 312,333

'6 Claims.

This invention relates to improvements in thread control mechanisms for weft replenishing looms and it is the general object of the invention to provide means for equalizing the load imposed upon the loom by a pneumatic system of thread control. v

I have heretofore proposed a pneumatic thread holder for weft replenishing looms wherein an air pump driven by the loom supplies thenecessary suction to -attract the thread extending Vfrom reserve bobbins. When relatively thick yarns Vare used and the magazine has been freshly filled the large Volume of the thread ends extending into the intake mouth materially reduces the. cross section of that part of the mouth through which air is drawn by the pump, and the resistvance to the ow of air under these conditions imposes a heavy load on the loom to operate the pump. As successive replenishments occur the threads are removed one by one and the incident to the operation of the `air pump it is an important object of my present invention to employ a compensating relief valve introduced into the pneumatic system in such a way as to afford an auxiliary inlet which is opened by atmospheric pressure when the sub-atmospheric pressure created by the pump within the system falls below a given amount due to resistance of the intake mouth. As the -number of threads in the thread holderdecreases there is a corresponding drop in the pneumatic resistance fand Ythe compensating valve has less tendency to open) The compensating valve is set, howeven. so that sufficient draft will always be providedeat-the intake mouth to draw into the intake mouth the thread of the freshly transferred bobbin.

I prefer to set the valve so that 'it will be closed when the intake mouth of lthe thread holder is empty and open varying mounts -depending upon the extent to which the we'ft threads reduce the air transmitting cross-section of area of the thread holder. v

In the operation of a weft replenishing loom it is essential that the shuttle to be replenished Cil in order to receive theincoming reserve bobbn.

Should the shuttle fail to reach transfer position because of a weak pick, or rebound from proper position because of too strong a pick, mechanisms areprovided which either prevent transfer or stop Ithe loom, depending upon the extent to which the shuttle is misplaced. VAny mechanism which derives lpower for its operation from the loom should thereforeY create a uniform power demand on the loom to prevent variations in the picking. It is another object of my yinvenf tion to provide a method -foroperating weft replenishing looms equipped with pneumatic thread control devices whereinV substantial constancy of power avail-able for picking' Vis insured by the provision of a compensator connected to the pneumatic system ,and responding lto Variations in the effective air transmitting part of the holder to impose substantially the same load on the loom without regard to the number of thread ends extending from the magazine into the thread holder.

AWith these and other objects inV viewwhich will appear as the description proceeds, my invention resides in the combination and arrangement of parts hereinafter described and set forth.

In the accompanying 'drawings wherein vtwo forms of myv invention are shown,

Fig.V 1 is a diagrammatic end elevation of a loom showing a pneumaticV 4thread removing system with the preferred form lof my invention applied thereto,

Fig; 2 is a plan View on an enlarged scale looking in the direction of arrow 2, Fig. 1, e

Fig. 3 is a Vertical section on line 3-- 3 of Fig. `2, Fig. 4 is a View similar to Fig. 3 but with the compensating valve openingA and the air pump shown as operating to`createfsub-atmospherifc pressures in the conduit connecting it with the Fig. 5 is a section on line l5--5 vof Fig. 3, f

Fig. 6 is an enlarged vertical section von"y line 5-5 of Fig. 1 takentransversely Aof the intake mouth or the Ythread holderrvand showing a relatively large number of weft ends partially blocking the mouth,

Fig. 7 is a view similar to Fig. 6 but witnyery few threads blockingv the mouth ofthe thread holder, v i' Fig. 8 is a plan viewv taken in the direction of arrow 8,Fig.'1 of a modified form ofvmy invention, Fig. 9 is a vertical section on line 9---9 of Fig, 8,

and v Fig. lo is a diagrammatic fronti. elevationof Y a Vloom showing ltheA picking mechanism' and the pump lfor the pneumatic system, together with the magazine for reserve bobbins and other parts.

Referring particularly to Fig. 10, the loom frame I supports top and bottom shafts II and I2, respectively, which are driven in the usual 2 1 ratio by gearing I3 driven by a source of power P. The top shaft Il drives the lay L through connectors one of which is shown at I4, Fig. 1. The bottom shaft carries picking arms I5 which actuate picking levers IB connected in the usual manner to picker sticks I1 actuated alternately to drive a shuttle S back and forth across the lay in usual manner. The picking arms are set in such a way that they actuate the picker sticks on rearward beats of the lay and the force of the pick is proportional among other things to the speed of the loom. Any material variation in loom speed will affect the picking so that the shuttle S will not beA properly positioned for transfer with respect to the magazine M.

The magazine M is preferably of .the multicolor type as shown more particularly in Fig. 1 and carries reserve bobbins B from which extend two sets of weft ends W and W. These weft threads lead to a thread holder designated generally at H which includes in its construction a tubular thread receiver I8 in which is located a block I9 extending part way across the internal bore of the tube I8 to produce a restricted air passage which communicates directly with an accumulator A supported by a bracket 2| and having a cylinder 22 which receives and holds threads transmitted through Resting on the cylinder of the preferred form of the invention is a cover 23 connected with the forward end of a tube or pipe 24 the rear end `of which extends to a vacuum.- pump designated generally at V. The pump is supported by a bracket 25 bolted to the loomside and comprises a horizontal cylinder 26 in which reciprocates a piston 21 on the forward end of a rod 28. The latter is connected as at 29 to the upper end of alever 30 pivoted aft its lower end at 3| to a pivot fixed with respect to the loom,. The intermediate part of the lever 3l) is connected at 32 to a forwardly extending rod 33 pivoted at 34 to the lay L.

The magazine M is rocked about a fixed stud i 35 by a rod 36 connected to a lever 31 pivoted at 38 and connected to a depending rod 43 moved in coordination with the shifting of the shuttle boxes 39 and 4,respectively, shown at the oppositeend of the loom, see Fig. l0. understood lthat the loom operates with two weaving shuttles-either of which may become active and that when one of the weaving shuttles is active the magazine will befrocked to an angular position-to permit transfer of one character of reserve weft and that when the other weaving shuttle is active the magazine will be rocked tothe opposite position to permit transferV ofthe reserve weft of another character. W'hile I have illustrated my invention in connection with a multi-weft loom I do not wish necessarilyvto be limited to such looms in the use of nty invention. Transfer is effected by a transfer arm 4l actuated in the usual manner by bunter 42 on the lay and latch 45 ,connected to the transfer arm.

The general characteristics of the loom as shown in Fig. 10 are of usual construction, and the. pneumatic Yfeatures except as pointed out hereinafter, are similar .to those already pro- Itis to be posed by me and set forth in greater detail in my prior Patents Nos. 2,199,353 and 2,199,354.

It is thought sufficient for present purposes to state that on each backward motion of the lay the piston 21 will be moved rearwardly in a direction from the full toward the dotted line position of Fig. 4, thereby creating sub-atmospheric pressures in the front of the cylinder and also in pipe 24. It is on the backward stroke of the lay that'the shuttle is ordinarily picked subsequent to a replenishing operation and the threads W and W' are therefore acted upon pneumatically to move in a direction toward the interior of the accumulator when the freshly replenished shuttle is picked to assist selfthreading of the shuttle.

Referring particularly to Figs. 6 and 7 I have illustrated two conditions which can exist during the operation of the loom, Fig. 6 showing the condition when the magazine is full of reserve bobbins and there is a comparatively large number of weft ends W and W' leading to the thread holder. In this case 'the restricted zone 20 will be occupied by a'large volume of threads as indicated at in Fig. 6 leaving only a small air space 5I for the passage of air toward the accumulator. In Fig. "l, on the other hand, I have illustrated the condition which exists when the magazine is almost empty, at which time there will be very few Weft ends extending from the reserve bobbins and yarn space 52 occupies a small part only of the passage 20, leaving a relatively large air space 53.

It will be apparent from an inspection of Figs. 6 and 7 that a considerable variation exists in the pneumatic resistance offered to the passage of air through zone 2D, depending upon the number of bobbins in the magazine, and this variation is reflected in the amount of load which the kvacuum pump V places on the loom driving motor. In the condition shown in Fig. 6 the pump will require considerable power for its operation and may therefore reduce the speed of the loom sufficiently to affect picking, while under the condition shown in Fig. 7 the pneumatic resistance is reduced to such a point that the pump requires much less power for its operation and there is therefore a greater amount of loom power available for picking.

My present invention provides means to compensate for the `varying load placed on the pump due to changes in the number of bobbins in the magazine to the lend that the loom speed may remain constant. In the preferred formI of my invention shown particularly in Figs. 2 to 4, I place in pipe 24 a compensating valve C comprising a casing B0 having a cylindrical body 6I into which extend tubes 62 and 63 connectedto parts of pipe 24 and in which is located a compression spring 65. The latter holds a valve plate 66 yieldingly against a valve seat B1 formed in a head 68 secured to the cylindrical casing 6I. An inlet port S9 communicates with the atmosphere but is normally closed by plate 63.

Referring to Figs. 8 and'9 I have shown a modified form of my invention wherein the accumulator is provided with a cover 10 formed with a well 15 fthe bottom of which is perforated as Vat 16 to communicate with lthe interior of cylinder 22. The-top of the well is partially closed by a cover "having an opening or port 18 therein normally closed by a valve plate -19 corresponding to plate 65 of the preferred form.- A light compression spring is located between the bottom of the well 15 ,and the valve 19 and mally spring closed to the atmosphere, said air pump and pneumatic connections and valve constituting a normally closed pneumatic system and the valve remaining closed so long as pneumatic pressure within the system is at or above av given sub-atmospheric pressure, reduction of the pneumatic pressure within the system below said given pressure due to partial closure of the intake mouth by the weft threads resulting in opening of the valve by atmospheric pressure to relieve the pump from the necessity of creating excessive sub-atmospheric pressures within the system. v

4. In a weft replenishing loom having a magazine provided with reserve bobbins from which weft threads extend to -a pneumatic thread holder, said thread holder having an intake mouth to receive the weft threads, an air pump driven by power derived from the loom, pneumatic connections between the air pump and the intake mouth, the air pump creating a normal sub-atmospheric pressure within the connections to draw the weft threads into said intake mouth, and a normally closed but yieldable compensating valve in said pneumatic connections,

said pump and connections and valves normally constituting a closed pneumatic system, the creation of pneumatic pressures within the system below the normal sub-atmospheric pressure due to partial closing of the intake mouth by weft threads resulting in opening of the compensating valve by atmospheric pressures to relieve the pump of the necessity of creating excessive sub-atmospheric pressures within the system.

5. In a weft replenishing loom having a magazine provided with reserve bobbins from which weft threads extend to a pneumatic thread holder, said thread holder having an intake mouth to receive the weft threads, an air pump driven by the loom to create sub-atmospheric pressures, pneumatic connections between the pump and the intake mouth to cause the pump to create sub-atmospheric pressures within the intake mouth and draw into the latter the weft threads extending from the bobbins, a compensating valve located in the pneumatic connections normally closing the interior of said connections to the atmosphere, and a yielding element to hold the valve closed when the sub-atmospheric pressure within the connections is at or above a given normal sub-atmospheric pressure and yieldable to permit opening of the valve by atmospheric pressures to establish communication between the atmosphere and the interior of said connections when pneumatic pressure Within the connections falls below said given normal pressure, partial closure of the intake mouth by weft threads to an extent sufficient to increase the resistance to the intake of air into the intake mouth to a point which causes the pump to create subnormalsub-atmospheric pressures within the connections resulting in opening of the compensating valve by atmospheric pressure against the action of the yielding element to establish communication between the atmosphere and the interior of said connections and relieve the pump of the necessity of creating excessively low pressures within said connections.

6. In a weft replenishing loom having a magazine provided with reserve bobbins from which weft threads extend to a pneumatic thread holder, succeeding transferring operations of the loom diminishing the number of threads which extend to said holder, the latter having an intake mouth to receive the weft threads, a pump operated by the loom to create sub-atmospheric pressures, a closed pneumatic system including the ptunp and connecting the latter with the intake mouth by which sub-atmospheric pressures are created by the pump within the intake mouth to draw the weft threads into said mouth, the weft threads partially closing the intake mouth and the extent of closing the mouth depending upon the number of weft threads present in said mouth and the resistance to passage of air under atmospheric pressures into the mouth diminishing as the number of weft threads extending into said mouth decreases, and a normally closed compensating valve located in the pneumatic system to keep the system lclosed when normal sub-atmospheric pressures exist within the system, the compensating valve opening Varying amounts by atmospheric pressure when dierent degrees of subnormal sub-atmospheric pressures exist within the system, a large number of weft threads in the mouth oiering relatively high resistance to passage of air into the mouth and thereby causing relatively low subnormal pressures within the system resulting in a large opening of the valve, and a small number of threads in the mouth oiering lower resistance to the passage of air into the mouth and kthereby causing relatively rhigh subnormal pressures within the system resulting in a small opening of the valve, the opening of the valve connecting the normally closed system of the atmosphere'and thereby relieving the pump of the necessity of creating excessively low sub-atmospheric pressure and tending to maintain normal sub-atmospheric pressures within the system.

RICHARD G. TURNER. 

